The present invention is directed to a primary and secondary conveyor belt cleaning system wherein a replaceable scraper blade is removably secured within a reusable blade support. The system includes such “key components” such as blades, and/or blade supports and/or mounting bars which are manufactured and inventoried in longer than needed “standard lengths” by the manufacturer, to be later “cut to size” and combined with “common components” such as locally available pipe or tubing serving as a support member, post-manufacture by the distributor or end user. This serves to economize on manufacturing and inventory costs.
The system further includes: separable scraper blades and supports; reusable blade supports; pin, clip, retainer and/or shoulder-bolt blade fixing systems; and components machined with guide grooves and measurement demarcation for ease of alignment, assembly and cutting of components to custom sizes.
1. Conventional Belt Cleaners
Conveyor belt cleaners are used to remove materials that cling to the return run of belt conveyors after the conveyor has discharged its cargo. The cargo can be units such as letters or cartons or it can be a bulk solid such as sand or gravel. The material that does not discharge from the belt at the desired discharge locations through the action of gravity or centrifugal force accumulates on components or finds its way into the environment, causing productivity, safety and cleanliness problems.
Conveyor belt cleaners have also required the use of external tensioners which actuate the scraper blades into biased engagement with the conveyor belt. A tensioner of various types is used to impart torque to the frame thus engaging it with the conveyor belt and maintaining contact throughout the life of the blade. Most tensioners require intermediate adjustment during the wear life of the blade to maintain optimum blade cleaning performance.
The blade components of conveyor belt cleaners wear out with use and need to be replaced periodically. Several manufacturers such as Argonics®, ASCGO®, ARCH®, FLEXCO® and Applicant's MARTIN® QC#1™ product have provided “quick change” cleaners which attempt to facilitate the process of blade replacement. Typically, in such conventional “quick change systems” a one-piece blade assembly sits on an upstanding flange which is supported by a frame typically made of round or rectangular steel tubing. The blade of such conventional “quick change” systems is held on the flange by 2 pins, usually one at each end. One pin is easily removable for quick service. Another typical retaining means is a fixed pin at one end and a removable pin at the same end. An aluminum extrusion is molded to the urethane blade in such conventional systems by a series of steps that require metal preparation and bonding agents.
The existing blade designs are made of cast polyurethane with an extruded aluminum support molded into the base that corresponds to the upstanding flange. An aluminum extrusion is used because complex configurations can be extruded to mechanically lock the urethane to the aluminum in addition to chemical bonding. The aluminum extrusion is usually cut to length prior to molding and either a slot or hole machined at each end to accept the retaining means.
Pre-engineered belt cleaners, wherein the belt cleaners are custom made to size for a particular application subject to the particular belt specifications of the end user, have been popularized over the last 25 years. There is now a proliferation of mechanical belt cleaning devices marketed by dozens of firms with domestic and international marketing capabilities. Because of the now accepted benefits of using engineered belt cleaners, there is a substantial volume of sales and pressure from the market for lower priced equipment with improved quality and performance. Several elements of the inventive belt cleaner disclosed and claimed herein address these industry needs.
Pre-engineered belt cleaners are exclusively marketed as “made to order” items in various assembly lengths to match standard belt widths. Applicant's QC#1™ system is an example of an economical engineered belt cleaner. The QC#1™ belt cleaner is a one-pin blade fixing and replacement system wherein the belt cleaner is installed on the conveyor belt head pulley.
Belt widths are standardized in the United States and are established by the Conveyor Equipment Manufacturers Association (CEMA). Imperial belt widths are generally in 6 inch increments starting at 6 inches up to 144 inches. The metric belt width standards are nominally set by the European ISO committees that specialize in conveyor belting. Metric belt widths are in increments of 100 mm and 150 mm starting from 150 mm and going up to 3000 mm wide belts. Thus there are over 50 standard belt cleaner sizes that must be manufactured, packaged and shipped to cover both markets. Most manufacturers use distributors to reach the end users. However, some sell direct, by mail order catalog or local sales representatives.
The current state of the art offers several blade widths equal to or shorter than the belt width. Belt width minus 50 mm, 75 mm or 150 mm and, belt width minus 2-inches, 3-inches or 6-inches are the most common.
To reduce inventory and improve delivery time most manufacturers offer additional engineered belt cleaner designs that are matrices of common components that are mounted on support structures. Normal intervals are one common subassembly for every 100 mm or 150 mm and 4-inches or 6-inches of belt width. In this way all of the common belt widths can be accommodated and only the support structure has to be made to size. Some of the simple designs use a single blade rather than a multiple of common sub components. However, in such cases the manufacturer still manufactures the blade “to size” performing the necessary machining and molding to adapt the blade to the customer length support structure. Pipe and square mechanical tubing are commonly used for support structures. While there is no formal industry standard, pipe sizes of 1½ inch or 2 inch iron pipe are commonly used. Some manufacturers ship the products completely assembled and others ship at the component level. Most shipments to the end user are at least partially assembled to reduce the chance of missing parts or shipping errors.
Additionally, there currently is an after-market for replacement part sales. Accordingly, manufacturers tend to price their replacement parts in such a way that the distributor can not increase its profit without the manufacturer benefiting in the increased margins by buying parts and assembling cleaners “to order” at its facility. Thus, most of the belt cleaners are currently shipped in “made to order” sizes either to the distributor or directly to the end user.
Accordingly, the prior art made to order belt cleaners have drawbacks when it comes to such things as: the need to make, store and ship many different sizes of cleaners and blades; wasted material; inefficiency; and longer than desired delivery times and shipping charges.
In order to address the problem of the over 50 standard belt cleaner sizes needed to accommodate both metric and imperial measurement belt width standards, the system of the present invention reduces: manufacturing costs; inventory; delivery time; inefficiency and waste, while providing end users with customized solutions closer to the point and time of use and making it easier to anticipate and prepare for reorders of the key components.
Additionally, presently available conveyor belt cleaners do not adequately address situations where the top or operational surface of the conveyor belt is non-uniform, such as when a crowned pulley is used or when the conveyor belt is worn. A rigid scraper blade and mounting system does not adequately take into account for changes in the profile of the top or operational surface of the conveyor belt and prevents the scraper blade from maintaining scraping engagement throughout the entire width of the conveyor belt.
2. The Current Invention
Thus, the present invention provides a “quick change” primary and secondary belt cleaning system that allows for faster delivery to the end user, and reduced costs and waste, while allowing the distributor or end user to supply commonly available components to be combined with the key components supplied by the manufacturer in standard lengths such as 2775 mm (106.3 inches) lengths, so as to be cut to length by the distributor or end user at the location of assembly.
Under the system of the present invention, the Original Equipment Manufacturer (“OEM”) or Distributor stocks standard lengths of key components such as blades, and/or blade supports, and/or mounting bars. The OEM, end user or Distributor supplies the common components comprising the pipe or tubing to be used as the support structure and cuts the key and common components to the desired length. The OEM, end user or Distributor likewise welds the mounting bar to the pipe and assembles and installs the completed cleaner. Hence, the key components are supplied to the end user, OEM or Distributor in long lengths that can be cut to size and fabricated at point of use and no sooner than needed.
By molding the blade in longer than needed lengths the manufacturing cost is reduced. By supplying such standard lengths of blade, blade support and mounting bar, inventory is reduced from the approximately 50 sizes or so currently offered in the industry to only one standard size. By completing the assembly immediately prior to use the work in progress investment is lower and the ability to determine the needed size and deliver the right size is enhanced. Since the most common belt sizes range between 600 mm to 1200 mm and, 24 inches to 48 inches, several combinations of blade sizes can be cut to size from the standard length of the blade with minimized waste. The same is true with respect to the standard length blade supports, and mounting bars.
By offering such key components (blade, blade support and mounting bar) in standard lengths, the purchasing, ordering and inventory costs are greatly reduced. Inventory is reduced since only the standard length of key components need be manufactured, stored and shipped. Because such key components are manufactured, inventoried and shipped in only the standard, longer than needed lengths, it is easier for the manufacturer to predict and time the preparation and shipment of replacement key components based on sales histories and trends. By moving the assembly process from the manufacturing plant to as close to the end user and installation as possible, delivery time to the end user is thereby also reduced.
The current invention further provides for selling and shipping kits containing pre-cut key components and corresponding tensioners in a limited number of the most popular sizes of belt cleaners at the point of sale, (POS), outlets such as mine supply stores for combination with the readily available support frame structural elements. This avoids the need to manufacture, stock and ship over 50 standard belt cleaner sizes while still (1) accommodating the current belt width standards; (2) reducing: inventory; costs; delivery time; inefficiency and waste; and, (3) while providing end users with the ability to customize solutions, while making it easier for the manufacturer to forecast and prepare for reorders of the key components.
Additionally, the scraper blade and mounting bracket flex or bow along the x-axis, y-axis, or z-axis of each of the scraper blade and mounting bar to enable the scraping edge of the scraper blade to maintain scraping engagement with the entire width of the top or operational surface of conveyor belts with non-uniform profiles, such as belts on crown pulleys and worn belts.